Funny Car: Difference between revisions

The NHRA has strict guidelines for funny cars. Most of the rules relate to the engine. In short, the engines can only be [[V-8]]'s at 90 degrees. (The most popular design has been the 426 [[Chrysler]] [[Hemi]].) There can only be two [[poppet valve|valves]] per [[cylinder]] and [[supercharger]]s are restricted to a basic Roots type--19 [[inch]] (483 mm) rotor case length with a width of 11.25 inches (286 mm). The [[engine displacement]] can only be from 490- to 500 cubicin³ inches(8 to 8.2 L). Only single [[camshaft]]s are allowed. There are two common bore X stroke combinations. 4.18 X 4.50 (Called a 3/4 stroker) and 4.25 X 4.38 (called a 5/8 stroker). The 3/4 stroker is the most common combination used today and equals 496 ci.

Engine blocks are usually made out of forged aluminum. [[Crankshaft]]s are made from billet [[chrome]]-[[vanadium]] steel. Intake valves are [[titanium]] and of 2.40- inch (61 mm) diameter, while exhaust valves are 1.90- inch (48 mm) diameter made out of [[Inconel]]. Every funny car has [[ballistic blanket]]s covering specific parts of the engine prone to explosion.

Funny car fuel systems are key to their immense power. Most systems will deliver from 500 to 600 pounds (weight, pressure, force?) of fuel pressure at as much as 75 US gallons per minute (5 L/s). During a single run (Starting, burnout, backing up, staging, 1/4 mile) cars can burn as much as 15 US gallons (57 L) of fuel. The fuel mixture is usually 98-99% [[nitromethane]] with 1-2% [[alcohol]]. The ratio of fuel to air can be as high as 1:1. [[Compression ratio]]s vary from 6:1 to 7:1. The engines in Funny cars commonly exhibit varying [[piston]] heights and ratios that are determined by the piston's proximity to the air intake. Funny cars have a fixed [[gear ratio]] of 3.20 : 1 and have a [[reverser]]. [[Wheelbase]] is between 100 and 125 inches (2.54 and 3.18 m). The car must maintain a 3 in (76 mm) ground clearance.